1. Field of the Invention
The present invention relates to an electric-machine-rotor and a method of manufacturing such a rotor.
2. Description of the Related Art
In a rotor having a field coil and no auxiliary permanent magnets, a difference in the magnetic polarity of the claw poles does not cause any problem due to change in the winding direction of the field coil, the position of wire-ends thereof extending from a bobbin, or connection of the wire-ends and slip rings.
As disclosed in JP-A-7-123644, there is a rotor that has auxiliary permanent magnets between claw poles of a pair of pole cores to increase effective magnetic flux and output power. It is necessary for this kind of rotor that the permanent magnets polarize the claw poles in the same polarity as the field coil does when it is energized. Otherwise, sufficient output power can not be generated.